Susceptor support portion and epitaxial growth apparatus including susceptor support portion

ABSTRACT

A susceptor support portion of the present invention includes a susceptor shaft and a substrate lift portion. The susceptor shaft includes a support column and a plurality of arms that extend radially from the support column, the substrate lift portion includes a support column and a plurality of arms that extend radially from the support column, the arm of the susceptor shaft includes a first arm, a second arm coupled to the first arm, and a third arm coupled to the second arm, from the support column side of the susceptor shaft, the second arm being provided with a through hole which passes through the second arm in a vertical direction, and a width of the first arm of the susceptor shaft is smaller than a width of the second arm of the susceptor shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of co-pending U.S.Nonprovisional patent application Ser. No. 13/927,553, filed Jun. 26,2013, which claims priority to Japanese patent application serial number2013-066897, filed Mar. 27, 2013. Both are herein incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a susceptor support portion forsupporting a susceptor used at the time of forming an epitaxial film onthe surface of a semiconductor wafer and an epitaxial growth apparatusincluding the susceptor support portion.

2. Description of the Related Art

Generally, epitaxial wafers are manufactured by growing an epitaxialfilm on a semiconductor wafer, with an epitaxial growth apparatus. Theuniformity in the thickness of the epitaxial film is one of qualities ofthe epitaxial wafer, and a high-quality epitaxial wafer is conditionedon the fact that the distribution of film thickness is in apredetermined range within the surface of the wafer.

Generally, the thickness of an epitaxial film is influenced by thetemperature of a semiconductor wafer located below the film. Thesemiconductor wafer is heated through a susceptor, but a susceptorsupport portion is present at the rear surface of the susceptor. Due tothe presence of the susceptor support portion, a difference occursbetween the temperature of a shadowed part of the susceptor supportportion of the susceptor, seen from a heating apparatus disposeddownward, and the temperature of the other parts, which leads to aproblem that the temperature of the entirety of the susceptor does notbecome uniform.

In this regard, for example, JP-A-10-335435 and JP-A-2011-108765disclose a technique in which a susceptor support portion is formed of atransparent material such as quartz glass. However, even when thesusceptor support portion is formed of a transparent material, it hasbeen difficult to solve the above-mentioned problem.

Further, there is also a problem in that a susceptor is deformed due toexposure to a high-temperature environment, and the temperature of theentirety of the susceptor does not become uniform. In this regard,JP-A-2011-108765 discloses a technique in which a force for supporting asusceptor is strengthened by setting the number of arms of the susceptorsupport portion to four or more, and the susceptor is prevented frombeing deformed.

However, an increase in the number of arms of the susceptor supportportion leads to an increase in a part shadowed by the susceptor supportportion.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above-mentionedproblems, and to provide a susceptor support portion capable of reducingan influence on the heating of a susceptor and sufficiently supportingthe susceptor, and an epitaxial growth apparatus capable ofmanufacturing a high-quality epitaxial wafer by including the susceptorsupport portion.

According to an embodiment of the present invention, there is provided asusceptor support portion supporting a susceptor from below, within anepitaxial growth apparatus that forms an epitaxial film on a surface ofa semiconductor wafer placed on the susceptor having a through hole, thesusceptor support portion including: a susceptor shaft that supports thesusceptor and a substrate lift portion that supports the semiconductorwafer, wherein the susceptor shaft includes a support column and aplurality of arms that extend radially from the support column, thesubstrate lift portion includes a support column and a plurality of armsthat extend radially from the support column, the arm of the susceptorshaft includes a first arm, a second arm coupled to the first arm, and athird arm coupled to the second arm, from the support column side of thesusceptor support portion, the second arm being provided with a throughhole which passes through the second arm in a vertical direction, thearm of the substrate lift portion includes a first arm, a second armcoupled to the first arm, and a pedestal portion coupled to the secondarm, from the support column side of the substrate lift portion, a liftpin capable of passing through the through hole of the susceptor shaftand the through hole of the susceptor is provided between the pedestalportion and the semiconductor wafer, and a width of the first arm of thesusceptor shaft is smaller than a width of the second arm of thesusceptor shaft.

The width of the first arm of the susceptor shaft is preferably equal toor less than a diameter of the through hole of the susceptor shaft.

A width of the third arm of the susceptor shaft is preferably smallerthan a width of the second arm of the susceptor shaft.

The width of the third arm of the susceptor shaft is preferably equal toor less than the diameter of the through hole of the susceptor shaft.

A width of the second arm of the substrate lift portion is preferablysmaller than the width of the first arm of the substrate lift portion.

The width of the second arm of the substrate lift portion is preferablythe same as the width of the first arm of the susceptor shaft.

The support column of the susceptor shaft is preferably provided with acap that supports the susceptor.

The pedestal portion is preferably provided with a concave portioncapable of supporting a lower end of the lift pin.

According to another embodiment of the present invention, there isprovided an epitaxial growth apparatus forming an epitaxial film on asurface of a semiconductor wafer placed on a susceptor having a throughhole, including: a susceptor support portion that supports the susceptorfrom below, wherein the susceptor support portion includes a susceptorshaft that supports the susceptor and a substrate lift portion thatsupports the semiconductor wafer, wherein the susceptor shaft includes asupport column and a plurality of arms that extend radially from thesupport column, the substrate lift portion includes a support column anda plurality of arms that extend radially from the support column, thearm of the susceptor shaft includes a first arm, a second arm coupled tothe first arm, and a third arm coupled to the second arm, from thesupport column side of the susceptor shaft, the second arm beingprovided with a through hole which passes through the second arm in avertical direction, the arm of the substrate lift portion includes afirst arm, a second arm coupled to the first arm, and a pedestal portioncoupled to the second arm, from the support column side of the substratelift portion, a lift pin capable of passing through the through hole ofthe susceptor shaft and the through hole of the susceptor is providedbetween the pedestal portion and the semiconductor wafer, and a width ofthe first arm of the susceptor shaft is smaller than a width of thesecond arm of the susceptor shaft.

The susceptor support portion according to the present invention is ableto reduce an influence on the heating of the susceptor, and sufficientlysupport the susceptor. In addition, the epitaxial growth apparatusaccording to the present invention is able to manufacture a high-qualityepitaxial wafer by including the susceptor support portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an epitaxial growthapparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a susceptor shaft according to theembodiment of the present invention.

FIG. 3 is a schematic diagram of a substrate lift portion according tothe embodiment of the present invention.

FIGS. 4A and 4B are schematic diagrams illustrating operations of asusceptor support portion according to the embodiment of the presentinvention.

FIG. 5 is a schematic cross-sectional view of an epitaxial growthapparatus according to another embodiment of the present invention.

FIG. 6 is an exploded perspective view illustrating a configuration of areaction chamber in the embodiment of the present invention.

FIG. 7 is an exploded perspective view illustrating an outerconfiguration of the reaction chamber in the embodiment of the presentinvention.

FIG. 8 is an exploded cross-sectional view illustrating a configurationof a ceiling portion in the embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating an inner configuration of asidewall portion in the embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a reactive gas supplypassage in the embodiment of the present invention.

FIGS. 11A and 11B are schematic diagrams illustrating the reactive gassupply passage in the embodiment of the present invention.

FIGS. 12A and 12B are perspective views illustrating an example of aflow straightening plate in the embodiment of the present invention.

FIG. 13 is a partial cross-sectional view illustrating an example of asusceptor ring in the embodiment of the present invention.

FIG. 14 is a partial cross-sectional view illustrating another exampleof the susceptor ring in the embodiment of the present invention.

FIG. 15 is a plan view illustrating an example of a susceptor in theembodiment of the present invention.

FIG. 16 is a plan view illustrating another example of the susceptor inthe embodiment of the present invention.

FIG. 17 is an exploded cross-sectional view illustrating an example of agas exhaust tube in the embodiment of the present invention.

FIG. 18 is a perspective view illustrating an example of an upperreflector in the embodiment of the present invention.

FIG. 19 is a perspective view illustrating an example of a lowerreflector in embodiment of the present invention.

FIG. 20 is an exploded cross-sectional view illustrating a configurationof a ceiling portion in an epitaxial growth apparatus of the relatedart.

FIG. 21 is an exploded perspective view illustrating an outerconfiguration of a reaction chamber in the epitaxial growth apparatus ofthe related art.

FIG. 22 is a perspective view illustrating an example of an upperreflector in the epitaxial growth apparatus of the related art.

FIG. 23 is a perspective view illustrating an example of a lowerreflector in the epitaxial growth apparatus of the related art.

FIGS. 24A and 24B are graphs illustrating film thickness distributionsof an epitaxial film according to Experimental Example 1 and comparativeexample 1.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a susceptor support portion according to the presentinvention will be described with reference to the accompanying drawings.

As shown in FIG. 1, as an example, a susceptor support portion 100according to the present invention supports a susceptor 20 from below,within an epitaxial growth apparatus 200 that forms an epitaxial film onthe surface of a semiconductor wafer W which is placed on the susceptor20 having through holes 10. The susceptor support portion 100 includes asusceptor shaft 110 that supports the susceptor 20 and a substrate liftportion 120 that supports the semiconductor wafer W. The epitaxialgrowth apparatus 200 includes heating means 210 such as a halogen lampat its upper portion and lower portion.

As shown in FIG. 2, the susceptor shaft 110 includes a support column111 and a plurality of arms 112 that extend radially from the supportcolumn 111. The arm 112 of the susceptor shaft 110 includes a first arm113, a second arm 114 coupled to the first arm, 113, and a third arm 115coupled to the second arm 114, from the support column 111 side. Thesecond arm 114 is provided with a through hole 116 which passes throughthe second arm 114 in a vertical direction.

In addition, as shown in FIG. 3, the substrate lift portion 120 includesa support column 121 and a plurality of arms 122 that extend radiallyfrom the support column. The arm 122 of the substrate lift portion 120includes a first arm 123, a second arm 124 coupled to the first arm 123,and a pedestal portion 125 coupled to the second arm 124, from thesupport column 121 side.

As shown in FIGS. 1 to 3, a shank 111 of the susceptor shaft 110 isinserted into a shank 121 of the substrate lift portion 120, and isconfigured to be capable of vertical motion and rotation.

As shown in FIG. 1, a lift pin 130 capable of passing through thethrough hole 118 of the susceptor shaft 110 and the through hole 10 ofthe susceptor 20 is provided between the pedestal portion 125 and thesemiconductor wafer W.

In addition, as shown in FIG. 3, it is preferable to provide a concaveportion 126 in the pedestal portion 125 of the substrate lift portion120. The concave portion 126 is provided, and thus it is possible toprevent the lift pin from being inclined due to misalignment, and tolift up a plurality of lift pins at the same level. In addition, it isalso possible to prevent the lift pin from being folded.

The semiconductor wafer W can be moved relatively up and down by theabove-mentioned lift pin 130. Specifically, the susceptor 20 descends bymoving the susceptor shaft 110 downward from the state of FIG. 4A to thestate of FIG. 4B. The lift pin 130 passes through the through hole 10 ofthe susceptor 20, and thus the semiconductor wafer W is lifted uprelatively.

Reversely, the susceptor 20 ascends by moving the susceptor shaft 110upward from the state of FIG. 4B to the state of FIG. 4A. Thesemiconductor wafer W descends relatively, and is placed on thesusceptor 20. At this time, the through hole 10 of the susceptor 20 canbe formed in a tapered shape or a T-shape having a decreasing diameterdownward so that the lift pin 130 does not fall, and the leading end ofthe lift pin 130 can be formed in a shape corresponding thereto.

As shown in FIG. 2, the susceptor support portion 100 of the presentinvention is configured such that the width of the first arm 113 of thesusceptor shaft 110 is made to be smaller than the width of the secondarm 114, thereby allowing the susceptor support portion 100 to reducethe influence on the heating of the susceptor. In addition, the numberof arms is not reduce, and thus a force which supports the susceptor isnot deteriorated as compared to the susceptor support portion the samenumber of arms.

In addition, in order to further reduce the influence on the heating ofthe susceptor, the width of the first arm 113 of the susceptor shaft 110is preferably set to be equal to or less than the diameter of thethrough hole 116.

Specifically, the width of the first arm 113 of the susceptor shaft 110is preferably set to be equal to or more than 3.0 mm and less than 6.3mm. This is because, when the width is less than 3.0 mm, there is aconcern that the susceptor cannot be sufficiently supported, and whenthe width is equal to or more than 6.3 mm, there is a concern that theinfluence on the heating of the susceptor may increase.

Similarly, the width of the third arm 115 of the susceptor shaft 110 ispreferably set to be smaller than the width of the second arm 114 of thesusceptor shaft 110.

Similarly, the width of the third arm 115 of the susceptor shaft 110 ispreferably set to be equal to or less than the diameter of the throughhole 116 of the susceptor shaft 110.

In addition, as shown in FIG. 3, in order to further reduce theinfluence on the heating of the susceptor, the width of the second arm124 of the substrate lift portion 120 is preferably set to be smallerthan the width of the first arm 123 of the substrate lift portion 120.

Specifically, the width of the second arm 124 of the substrate liftportion 120 is preferably set to be equal to or more than 2.0 mm andless than 4.8 mm. This is because, when the width is less than 2.0 mm,there is a concern that the lift pin cannot be sufficiently supported,and when the width is equal to or more than 4.8 mm, there is a concernthat the influence of the heating of the susceptor may increase.

In addition, the width of the second arm 124 of the substrate liftportion 120 may be set to be the same as the width of the first arm 113of the susceptor shaft 110.

In addition, as shown in FIG. 2, the susceptor shaft 110 preferablyincludes an arm 117 on the support column side for coupling thesemembers to each other, between the support column 111 and the first arm113, and the width of the arm 117 on the support column side ispreferably set to be larger than the width of the first arm 113 of thesusceptor shaft 110. This is because the coupling of the support column111 of the susceptor shaft 110 to the arm 112 thereof is strengthened.

In addition, the susceptor shaft 110 and the substrate lift portion 120are preferably formed of transparent quartz. This is because radiantheat from the heating apparatus 210 can be sufficiently transmitted tothe susceptor 20.

Further, a cap for increasing a force which supports the susceptor 20can also be provided on the upper portion of the support column 111 ofthe susceptor shaft 110.

Meanwhile, in the drawing, the number of arms is set to three, but canbe increased as necessary.

Subsequently, an embodiment of the epitaxial growth apparatus accordingto the present invention will be described with reference to theaccompanying drawings.

As shown in FIG. 1, as an example, the epitaxial growth apparatus 200according to the present invention forms an epitaxial film on thesurface of the semiconductor wafer W which is placed on the susceptor 20having the through hole 10.

The epitaxial growth apparatus 200 includes a reaction chamber 2. Thereaction chamber 2 is constituted by the susceptor 20 on which thesubstrate W is placed, a sidewall portion 4, and a ceiling portion 5.

The susceptor 20 is a plate-like member having a circular shape in a topsurface view, and is configured to be slightly larger than the substrateW. The susceptor 20 is provided with a concave portion 3 a for asubstrate for placing the substrate W. The susceptor 20 is supported bythe susceptor support portion 100 having a plurality of arms.

The susceptor 20 is configured such that an annular susceptor ring 7 isdisposed in its periphery at a film forming position P1. The susceptorring 7 is supported by a flange portion 13 provided in the sidewallportion 4 of the reaction chamber 2.

The ceiling portion 5 is constituted by a ceiling plate 21 and a supportportion 22 that supports the ceiling plate 21. The ceiling plate 21 haspermeability, and is configured to be capable of heat the inside of thereaction chamber 2 by transmitting heat from the heating means 210 (forexample, halogen lamp) and an upper reflector 26 which are providedabove the outside of the ceiling plate 21. That is, the epitaxial growthapparatus 200 in the present embodiment is a cold wall-type epitaxialgrowth apparatus. In the present embodiment, quartz is used as theceiling plate 21.

The support portion 22 that supports the ceiling plate 21 is annular.The ceiling plate 21 is fixed to the end of a through hole 24 on thesubstrate W side which is located further inside than the inner edge ofthe support portion 22. A fixing method includes welding.

The sidewall portion 4 is constituted by an annular upper sidewallportion 31 and an annular lower sidewall portion 32. The above-mentionedflange portion 13 is provided on the inner circumferential side of thelower sidewall portion 32. The support portion 22 is disposed on theupper sidewall portion 31.

A gap 35 between a first concave portion 34 of the lower sidewallportion 32 and a first convex portion 36 of the upper sidewall portion31 functions as a reactive gas supply passage 41 (supply passage).

Similarly, a gap 38 between a first concave portion 37 of the lowersidewall portion 32 and a first convex portion 39 of the upper sidewallportion 31 functions as gas exhaust passage 42.

In this manner, the reactive gas supply passage 41 and the gas exhaustpassage 42 face each other in the reaction chamber 2, and a reactive gasflows on the substrate W in a horizontal direction in the reactionchamber 2.

An annular placing table 45 is provided on the lower surface side of thelower sidewall portion 32 of the sidewall portion 4, and the sidewallportion 4 is placed on the placing table 45.

An annular clamping portion 51 is provided on the outer circumferentialside of the ceiling portion 5, the sidewall portion 4, and the placingtable 45, and the annular clamping portion 51 clamps and supports theceiling portion 5, the sidewall portion 4 and the placing table 45. Theclamping portion 51 is provided with a communication passage 52 on thesupply side that communicates with the reactive gas supply passage 41and a communication passage 53 on the exhaust side that communicateswith the gas exhaust passage 42. A gas introduction tube 55 is insertedinto the communication passage 52 on the supply side. In addition, a gasexhaust tube 58 is inserted into the communication passage 53 on theexhaust side.

The reactive gas introduction portion 54 is provided on the outside ofthe clamping portion 51, and the reactive gas introduction portion 54and the communication passage 52 on the supply side communicate witheach other. In the present embodiment, a first raw material gas and asecond raw material gas are introduced from the reactive gasintroduction portion 54. Meanwhile, the second raw material gas alsofunctions as a carrier gas. As a reactive gas, a gas obtained by mixingthree or more kinds of gases can also be used. The connection portionbetween the communication passage 52 on the supply side and the reactivegas introduction portion 54 is provided with a flow straightening plate56 so as to be perpendicular to a gas passage. The flow straighteningplate 56 is provided with a plurality of hole portions 56 a arranged ina low along the circumferential direction, and the reactive gas passesthrough the hole portions 56 a. Therefore, the first raw material gasand the second raw material gas are mixed and straightened. In addition,a gas exhaust portion 57 is further provided on the outside of theclamping portion 51. The gas exhaust portion 57 is provided at aposition facing the reactive gas introduction portion 54 with the centerof the reaction chamber 2 interposed therebetween. The gas exhaustportion 57 and the communication passage 53 on the exhaust sidecommunicate with each other. That is, the reactive gas introductionportion 54 is connected to the reactive gas supply passage 41 throughthe communication passage 52 on the supply side. In addition, the gasexhaust portion 57 is connected to the gas exhaust passage 42 throughthe communication passage 53 on the exhaust side. The gas exhaustpassage 42 is provided so as to face the reactive gas supply passage 41with the center of the reaction chamber 2 interposed therebetween.

In addition, a bottom 61 of the apparatus is provided on the lowerportion on the inner circumferential side of the placing table 45.Another heating means 62 and the lower reflector 65 are provided on theoutside of bottom 61 of the apparatus, and can heat the substrate W frombelow.

A shank 63 of the susceptor support portion 100 is inserted in thecenter of the bottom 61 of the apparatus, and a purge gas introductionportion (not shown) into which a purge gas is introduced is providedtherein. The purge gas is introduced into a lower portion 64 of thereaction chamber which is constituted by the bottom 61 of the apparatus,the lower sidewall portion 32 and the placing table 45, from purge gasintroduction means, not shown, provided in the purge gas introductionportion.

The susceptor support portion 100 that supports the susceptor 20 frombelow is as described above.

The configuration of an epitaxial growth apparatus 200 according toanother embodiment of the present invention will be described in detailwith reference to FIGS. 5, 6 and 7. FIG. 5 is a cross-sectional viewillustrating the entirety of the epitaxial growth apparatus 200. Inaddition, FIG. 6 is an exploded perspective view illustrating aconfiguration of the reaction chamber 2 according to the epitaxialgrowth apparatus 200, and FIG. 7 is an exploded perspective viewillustrating an outer configuration of the reaction chamber 2 accordingto the epitaxial growth apparatus 200.

The epitaxial growth apparatus 200 is a film formation apparatus forepitaxial growing a film such as, for example, silicon on the substrateW.

The epitaxial growth apparatus 200 includes a reaction chamber 2. Thereaction chamber 2 is constituted by the susceptor 20 on which thesubstrate W is placed, a sidewall portion 4, and a ceiling portion 5.

The susceptor 20 is a plate-like member having a circular shape in a topsurface view, and is configured to be slightly larger than the substrateW. The susceptor 20 is provided with a concave portion 3 a for asubstrate for placing the substrate W. The susceptor 20 is supported bythe susceptor support portion 100 having a plurality of arms.

The susceptor support portion 100 elevates the susceptor 20 whilesupporting the susceptor 20. The elevation range of the surface of thesusceptor 20 on which the substrate W is placed is susceptor 20 is arange from a film forming position P1 at which film formation isperformed on the substrate W to a substrate conveying position P2 atwhich the substrate W is transferred into and from the epitaxial growthapparatus 200. The susceptor support portion 100 is configured to rotateat the film forming position P1 using the axis of the susceptor supportportion 100 as the center of rotation, thereby allowing the susceptor 20and the substrate W to be rotated.

The susceptor 20 is configured such that an annular susceptor ring 7 isdisposed in its periphery at a film forming position P1. The susceptorring 7, of which the details will be described later, is constituted bya first ring 11 and a second ring 12 placed on the first ring 11. Thesusceptor ring 7 is supported by a flange portion 13 provided in thesidewall portion 4 of the reaction chamber 2.

The ceiling portion 5 is constituted by a ceiling plate 21 and a supportportion 22 that supports the ceiling plate 21. The ceiling plate 21 haspermeability, and is configured to be capable of heat the inside of thereaction chamber 2 by transmitting heat from the heating means 210 (forexample, halogen lamp) and an upper reflector 26 which are providedabove the outside of the ceiling plate 21. That is, the epitaxial growthapparatus 200 in the present embodiment is a cold wall-type epitaxialgrowth apparatus. In the present embodiment, quartz is used as theceiling plate 21.

The support portion 22 that supports the ceiling plate 21 is annular.The ceiling plate 21 is fixed to the end of a through hole 24 on thesubstrate W side which is located further inside than the inner edge ofthe support portion 22. A fixing method includes welding.

The sidewall portion 4 is constituted by an annular upper sidewallportion 31 and an annular lower sidewall portion 32. The above-mentionedflange portion 13 is provided on the inner circumferential side of thelower sidewall portion 32. A substrate conveying port 30 is provided atthe side located further down than the flange portion 13. The uppersidewall portion 31 has an inclined plane, corresponding to an outerinclined plane of a protruding portion 25 of the support portion 22, onits upper surface. The support portion 22 is disposed on the inclinedplane of the upper sidewall portion 31.

The upper surface of the lower sidewall portion 32 is configured suchthat a portion of the outer circumferential portion is notched, and aregion in which the notch is provided is formed as a placing surface 33on which the upper sidewall portion 31 is placed. A first concaveportion 34 is formed in the lower sidewall portion 32 by the notch ofthe lower sidewall portion 32. That is, the first concave portion 34 isa concave portion formed in a portion in which the placing surface 33 onthe upper surface of the lower sidewall portion 32 is not formed. Theupper sidewall portion 31 is provided with a first convex portion 36 sothat the convex portion corresponds to the shape of the first concaveportion 34 at a position corresponding to the first concave portion 34during placement on the lower sidewall portion 32, and that a gap 35 isformed between the convex portion and the first concave portion 34. Thegap 35 between the first convex portion 36 and the first concave portion34 functions as a reactive gas supply passage 41 (supply passage). Thedetails of the reactive gas supply passage 41 will be described later.

In addition, in a region facing the first concave portion 34 of thelower sidewall portion 32, the upper surface of the lower sidewallportion 32 is configured such that a portion of its outercircumferential portion is notched and a second concave portion 37 isformed. The upper sidewall portion 31 is provided with a second convexportion 39 so that the convex portion corresponds to the shape of thesecond concave portion 37 at a position corresponding to the secondconcave portion 37 during placement on the lower sidewall portion 32,and that a gap 38 is formed between the convex portion and the secondconcave portion 37. A gas exhaust passage 42 is formed between thesecond concave portion 37 and the second convex portion 39 of the uppersidewall portion 31.

In this manner, the reactive gas supply passage 41 and the gas exhaustpassage 42 face each other in the reaction chamber 2, and a reactive gasflows on the substrate W in a horizontal direction in the reactionchamber 2.

In addition, a purge hole 44 through which a purge gas is exhausted isformed in a wall surface 43 constituting the second concave portion 37of the lower sidewall portion 32. The purge hole 44 is provided belowthe flange portion 13. The purge hole 44 is provided in the wall surface43 constituting the second concave portion 37, and thus the purge hole44 fronts on the gas exhaust passage 42. Therefore, both the reactivegas and the purge gas are exhausted from the gas exhaust passage 42.

An annular placing table 45 is provided on the lower surface side of thelower sidewall portion 32 of the sidewall portion 4, and the sidewallportion 4 is placed on the placing table 45.

An annular clamping portion 51 is provided on the outer circumferentialside of the ceiling portion 5, the sidewall portion 4, and the placingtable 45, and the annular clamping portion 51 clamps and supports theceiling portion 5, the sidewall portion 4 and the placing table 45. Theclamping portion 51 is provided with a communication passage 52 on thesupply side that communicates with the reactive gas supply passage 41and a communication passage 53 on the exhaust side that communicateswith the gas exhaust passage 42. A gas introduction tube 55 is insertedinto the communication passage 52 on the supply side. In addition, a gasexhaust tube 58 is inserted into the communication passage 53 on theexhaust side.

The reactive gas introduction portion 54 is provided on the outside ofthe clamping portion 51, and the reactive gas introduction portion 54and the communication passage 52 on the supply side communicate witheach other. In the present embodiment, a first raw material gas and asecond raw material gas are introduced from the reactive gasintroduction portion 54. Meanwhile, the second raw material gas alsofunctions as a carrier gas. As a reactive gas, a gas obtained by mixingthree or more kinds of gases can also be used. The connection portionbetween the communication passage 52 on the supply side and the reactivegas introduction portion 54 is provided with a flow straightening plate56 so as to be perpendicular to a gas passage. The flow straighteningplate 56 is provided with a plurality of hole portions 56 a arranged ina low along the circumferential direction, and the reactive gas passesthrough the hole portions 56 a. Therefore, the first raw material gasand the second raw material gas are mixed and straightened. In addition,a gas exhaust portion 57 is further provided on the outside of theclamping portion 51. The gas exhaust portion 57 is provided at aposition facing the reactive gas introduction portion 54 with the centerof the reaction chamber 2 interposed therebetween. The gas exhaustportion 57 and the communication passage 53 on the exhaust sidecommunicate with each other. That is, the reactive gas introductionportion 54 is connected to the reactive gas supply passage 41 throughthe communication passage 52 on the supply side. In addition, the gasexhaust portion 57 is connected to the gas exhaust passage 42 throughthe communication passage 53 on the exhaust side. The gas exhaustpassage 42 is provided so as to face the reactive gas supply passage 41with the center of the reaction chamber 2 interposed therebetween.

In addition, a bottom 61 of the apparatus is provided on the lowerportion on the inner circumferential side of the placing table 45.Another heating means 62 and the lower reflector 65 are provided on theoutside of bottom 61 of the apparatus, and can heat the substrate W frombelow.

A shank 63 of the susceptor support portion 100 is inserted in thecenter of the bottom 61 of the apparatus, and a purge gas introductionportion (not shown) into which a purge gas is introduced is providedtherein. The purge gas is introduced into a lower portion 64 of thereaction chamber which is constituted by the bottom 61 of the apparatus,the lower sidewall portion 32 and the placing table 45, from purge gasintroduction means, not shown, provided in the purge gas introductionportion. In addition, the purge hole 44 communicates with the lowerportion 64 of the reaction chamber.

Outline of Growth Method Using Epitaxial Growth

Next, a growth method using the epitaxial growth apparatus according tothe present embodiment will be described.

First, the susceptor 20 is moved up to the substrate conveying positionP2, the substrate W is carried in from the substrate conveying port 30,and the susceptor 20 is moved up to the film forming position P1. As thesubstrate W, a silicon substrate having a diameter of, for example, 200mm is used. Next, the substrate is heated from standby temperature (forexample, 800° C.) to growth temperature (for example, 1100° C.) by theheating means 210. A purge gas (for example, hydrogen) is introducedfrom the purge gas introduction portion into the lower portion 64 of thereaction chamber. In addition, a reactive gas (for example,trichlorosilane as the first raw material gas, and hydrogen as thesecond raw material gas) is introduced from the reactive gasintroduction portion 54 through the reactive gas supply passage 41 intothe reaction chamber 2. The reactive gas forms a boundary layer on thesurface of the substrate W, and reaction occurs in the boundary layer.Thereby, a silicon film is formed on the substrate W. The reactive gasis exhausted from the gas exhaust passage 42 which fronts on thereaction chamber 2. In addition, the purge gas is exhausted to the gasexhaust passage 42 through the purge hole 44. In this manner, after theepitaxial growth is terminated, temperature is reduced up to the standbytemperature. The substrate W is then carried out, and is moved toanother chamber of a semiconductor manufacturing apparatus.

Details of Epitaxial Growth Apparatus and Method

Next, the details of components of the epitaxial growth apparatus 200according to the present embodiment will be described, and the detailsof a growth method according to the present embodiment will also bedescribed.

FIG. 8 is an exploded cross-sectional view illustrating a configurationof the ceiling portion 5 in the present embodiment. As shown in thedrawing, the inner edge of the support portion 22 that supports theceiling plate 21 gradually decreases in diameter toward the substrateside. The ceiling plate 21 is fixed to the end of the inner edge on thesubstrate W side. In addition, when the support portion 22 is seen fromthe rear surface side (lower surface side), the inner circumferentialportion protrudes and is formed as the protruding portion 25. Theprotruding portion 25 is also formed so as to gradually decrease indiameter toward a protruding direction. In this manner, the supportportion 22 is constituted by two inclined planes. That is, in theperipheral portion of the ceiling plate 21, the support portion 22supports the ceiling plate 21 from the upper and outer sides of theperipheral portion. On the other hand, FIG. 20 is an explodedcross-sectional view illustrating an example of a ceiling portion 5′ ofan epitaxial growth apparatus of the related art. As shown in thedrawing, in the ceiling portion 5′ of the apparatus of the related art,a support portion 22′ supports a ceiling plate 21′ from the same planeas the ceiling plate 21′, in the peripheral portion of the ceiling plate21′, and the support portion 22′ is formed in a shape having asubstantially right-angled corner 25′.

In this manner, in the present embodiment, the support portion 22 isformed in a shape which is not likely to concentrate stress as comparedto that of the related art, and thus a distance H between the substrateW and the ceiling plate 21 can be set to be short, that is, less than 10mm.

Specifically, most of infrared rays from the heating means 210 passthrough the ceiling plate 21 (21′), but the ceiling plate 21 (21′)itself absorbs radiant heat from the susceptor 20 or the substrate W.This absorbed heat is input from the ceiling plate 21 (21′) through thejunction with the support portion 22 (22′) to the support portion 22(22′). Here, when the distance H between the substrate W and the ceilingplate 21 (21′) is shortened, the amount of the radiant heat absorbedincreases, and a great deal of heat which is input to the supportportion 22 (22′) occurs. Therefore, as in the ceiling portion 5′ of therelated art, when the support portion 22′ has the substantiallyright-angled corner 25′, stress is concentrated in the corner 25′, andthus there is a concern that a crack or the like may be generated.

In the other hand, in the present embodiment, the support portion 22 isprovided with the protruding portion 25, and in the peripheral portionof the ceiling plate 21, the ceiling plate 21 is supported from theupper and outer sides of the peripheral portion. Therefore, the ceilingplate 21 can be supported at the substrate side without providing thecorner (25′) having a tendency to concentrate stress, insofar aspossible.

In addition, in the present embodiment, the distance H between theceiling plate 21 and the substrate W is shortened in order to narrow theboundary layer as mentioned above, and thus the reactive gas has atendency to escape the outside of the substrate W. In addition, since acase where it is difficult to uniform the distribution of film thicknessin the substrate is considered, it is preferable to prevent this case.For this reason, in the present embodiment, the reactive gas supplypassage 41 is provided with a guide portion in order to uniform a gasflow, as described below.

The guide portion provided in the reactive gas supply passage 41 will bedescribed in detail with reference to FIG. 9 to FIGS. 11A and 11B. Asmentioned above, the reactive gas supply passage 41 is formed of thefirst concave portion 34 of the lower sidewall portion 32 and the firstconvex portion 36 of the upper sidewall portion 31, and communicates upto the reactive gas introduction portion 54 through the gas introductiontube 55 within the communication passage 52 on the supply side. Inaddition, the reactive gas supply passage 41 includes a first supplypassage 71 that extends in a direction (horizontal direction) consistentwith the introduction direction of a gas from the reactive gasintroduction portion 54, a second supply passage 72 that communicateswith the first supply passage 71 and extends in a direction (verticaldirection) perpendicular to the introduction direction of a gas, and athird supply passage 73 that communicates with the second supply passage72 and extends in a direction (horizontal direction) consistent with theintroduction direction of a gas. The third supply passage 73communicates with the reaction chamber 2. That is, the reactive gassupply passage 41 is formed in an ascending stepwise shape toward anoutlet connected from the communication passage 52 on the supply sidewhich is an inlet of the reactive gas to the reaction chamber 2 which isan outlet of the reactive gas.

Here, the second supply passage 72 extends in a vertical direction asmentioned above, and thus the gas introduced from the reactive gasintroduction portion comes into contact with a wall surface 74 facingthe reactive gas introduction portion 54 of the second supply passage72. Thereby, the reactive gas is diffused, and the miscibility of thereactive gas increases. That is, the second supply passage 72 functionsas a mixing chamber of the reactive gas. In this case, in the presentembodiment, a groove portion 75 extending in a vertical direction isformed in the wall surface 74 of the second supply passage 72 so thatthe reactive gas does not stagnates in the second supply passage 72, andthe groove portion 75 functions as the guide portion. In this manner,the groove portion 75 is provided, and thus the gas diffused by cominginto contact with the wall surface 74 of the second supply passage 72also has a tendency to flow into the third supply passage 73. Further,the gas is straightened along the groove portion 75, and thus it ispossible to improve the straightness of the reactive gas, and tosuppress the spread of the reactive gas when the gas flows into thereaction chamber 2.

The groove portion 75 will be described in detail. A plurality of grooveportions 75 are continuously formed as concave portions in the entirewall surface 74 of the second supply passage 72. As shown in FIG. 11A,the groove portion 75 which is a concave portion is curved in the widthdirection of the groove portion 75. In the present embodiment, thegroove portion 75 is arc-shaped in a top surface view. When the reactivegas comes into contact with the bottom of the groove portion 75 of thewall surface 74 due to the curvature of the groove portion 75 in thewidth direction, the reactive gas is not easily diffused (is easilyconcentrated). Even when the reactive gas flows into the reactionchamber 2, the reactive gas is not easily spread to the outside of thesubstrate W. Meanwhile, when the depth of the groove portion 75 isexcessively large, the diffusion thereof can be suppressed, but it isdifficult to mix the first raw material gas with the second raw materialgas in the reactive gas. In one embodiment of the present invention, thedepth of the groove portion 75 is preferably set to 1 mm to 5 mm.Further, the depth is more preferably set to 3 mm.

In addition, each of the groove portions 75 is provided so as to bedirected to the center C of the lower sidewall portion 32 in thein-plane direction. That is, the groove portion 75 is provided along thecircumferential direction of the lower sidewall portion 32. By providingthe groove portion in this manner, a straightening property is improvedso that a component in the horizontal direction toward the flow of thereactive gas which is guided by each of the groove portions 75 and isintroduced into the reaction chamber 2 is consistent with a component inthe horizontal direction from the center of an aperture of the reactivegas supply passage 41 on the reaction chamber 2 side toward the centerof the reaction chamber 2, and the dispersion of the reactive gas intothe reaction chamber 2 is suppressed.

Further, each groove portion 75 is provided at a position in which thecenter of each groove portion 75 in the width direction and the centerof the hole portion 56 a of the flow straightening plate 56 provided inthe reactive gas introduction portion 54 are substantially consistentwith (correspond to) each other. That is, in the present embodiment, thenumber of groove portions 75 and the number of hole portions 56 a in thewall surface 74 are consistent with each other. Thereby, since thereactive gas straightened by the flow straightening plate 56 flows tothe each groove portion 75 as it is, flow straightening action furtherincreases, and thus the straightness of the reactive gas can beimproved.

Meanwhile, in the present embodiment, the groove portions 75 areprovided in the entire wall surface 74 of the second supply passage 72,but may be provided in at least the end portion in the wall surface 74of the second supply passage 72. The end portion means a portioncorresponding to an endmost region of a plurality of regions into whichthe hole portion of the flow straightening plate 56 is divided. Forexample, in a case of FIG. 11B, the flow straightening plate 56 isdivided into three regions 81, the groove portions 75 may be providedcorresponding to the hole portions of endmost regions 82 and 83 in theregions. As mentioned above, the reactive gas has a tendency to escapeto the outside of the substrate W, and thus it is preferable to providethe groove portion 75 in order to improve the straightness of thereactive gas, particularly, in the end portion of the reactive gassupply passage 41. In this case, the groove portion 75 functioning asthe guide portion is formed as a concave portion, thereby allowing suchan effect to be easily obtained. For example, when a straighteningmember is separately provided in the second supply passage 72, problemssuch as the miscibility of the reactive gas and a manufacturing costoccurs. However, as in the present embodiment, the groove portion 75 isformed as a concave portion, and thus these problems are solved.

FIGS. 12A and 12B are perspective views illustrating an example of theflow straightening plate 56. As shown in the drawings, as the flowstraightening plate 56, a plate corresponding to a pattern of the grooveportion 75 may be prepared. The numerical aperture of the flowstraightening plate 56 is preferably determined to be an optimum valueincluding not only the viewpoint of a growth rate, but also incidentalfittings such as a scrubber or the shape and length of outer piping.

In the present embodiment, the distance between the ceiling plate 21 andthe substrate W is narrowed in order to narrow the boundary layer asmentioned above, and thus it is considered that the wrapping around ofthe reactive gas to the lower portion of the reaction chamber 2 has atendency to occur, and the temperature distribution of the substrate Wis not likely to be uniformed. As a result, the distribution of filmthickness or the deterioration in film quality during the formation of athick film (for example, the distribution of resistivity, the occurrenceof a crystal defect, or the like) is also considered. In the presentembodiment, the susceptor ring 7 is constituted by two members in orderto prevent this. Such a point will be described below.

As enlargedly shown in FIG. 13, the first ring 11 constituting thesusceptor ring 7 is separated from the outer circumference of thesusceptor, a stepped portion 91 having a low upper surface is formed onthe inner circumferential side of the first ring. The second ring 12 isplaced on the stepped portion 91. The second ring 12 fronts on aseparation portion 92 formed between the first ring 11 and the susceptor20, that is, is provided so as to protrude to the separation portion 92.The upper surface of the second ring 12 is provided so as to be equal tothe upper surface of the susceptor 20. In this manner, the upper surfaceof the second ring 12 is provided so as to be equal to the upper surfaceof the susceptor 20, and thus a reactive gas maintained in a state wherethe gas is mixed and straightened in the reactive gas supply passage 41or the like can be smoothly supplied to the substrate W without loweringits velocity insofar as possible. Meanwhile, the term “upper surface ofthe susceptor 20” as used herein means an upper surface of a region inwhich the concave portion 3 a for a substrate of the susceptor 20 (seeFIGS. 5, 6, 15, and 16) is not formed. In the second ring 12 of thepresent embodiment, silicon carbide is used as a material in view ofthermal conductivity.

In this manner, the second ring 12 and the first ring 11 are formed asdifferent members, and thus the susceptor ring 7 can be formed with ahigher degree of accuracy. That is, the distance between the susceptorring 7 and the susceptor 20 can be brought close to the limit. Thereby,it is possible to reduce the wrapping around of the reactive gas to therear surface side of the substrate W, that is, the lower portion 64 ofthe reaction chamber, and to uniform the temperature distribution of thesubstrate W. Thereby, in the present embodiment, the thicknessdistribution of the formed film or the distribution of film quality isuniformed.

In addition, two members of the first ring 11 and the second ring 12 areformed, and thus the transfer of heat between the first ring 11 and thesecond ring 12 can be further suppressed than in a case where the firstring 11 and the second ring 12 are formed as one member.

Further, in this manner, the second ring 12 is formed so as to front onthe separation portion 92, and thus it is possible to reduce the leakageof the reactive gas downward from between the susceptor ring 7 and thesusceptor 20 during the film formation. Therefore, the flow of thereactive gas is not likely to be disturbed, and it is possible to reducethe leakage of the reactive gas downward, thereby allowing the number ofparticles to be reduced.

In this case, the second ring 12 is formed to be thinner than the firstring 11. Thereby, it is possible to suppress a heat loss due toradiation from the susceptor 20. In addition, the second ring 12 isformed to be thin, and thus it is possible to reduce the amount ofheating required for maintaining (pre-heating) the second ring 12 at apredetermined high temperature. As another embodiment, when the firstring 11 is formed as a material having a low thermal conductivity, thefirst ring 11 functions as a heat insulating material, and thus it ispossible to further improve the above-mentioned effect.

Meanwhile, in the present embodiment, the second ring 12 is formed so asto front on the separation portion 92, but is not limited thereto. Whenthe second ring 12 is formed so as to be placed at least on the steppedportion 91 of the first ring 11, the susceptor ring 7 can be formed witha high degree of accuracy, and thus the distance between the susceptorring 7 and the susceptor 20 can be brought close to the limit. Thereby,it is possible to reduce the wrapping around of the reactive gas to therear surface side of the substrate W, and to uniform the temperaturedistribution of the substrate.

In addition, in the present embodiment, since the distance between theceiling plate 21 and the substrate W is narrowed in order to narrow theboundary layer, the ceiling surface of the ceiling plate 21 is alsoeasily coated by the reactive gas. When the ceiling surface is coated,the ceiling surface becomes dim, and thus there is a concern that a filmcannot be sufficiently formed in a cold wall-type epitaxial growthapparatus that performs heating from the heating means 210 through theceiling plate 21. On the other hand, in the present embodiment, thegroove portion 75 is provided in the wall surface of the reactive gassupply passage 41 as mentioned above, and the susceptor ring 7 isconstituted by two members. Therefore, the reactive gas is not likely tostagnate in the reaction chamber 2, and as a result, the adhesion of acoating material can be suppressed. Thereby, it is possible tocontinuously perform sufficient film formation.

FIG. 14 is a diagram illustrating a modified example of the susceptorring 7. The modified example is different from the embodiment shown inFIG. 13, in that a second ring 12A is provided so as to cover aseparation portion 92A. In the modified example, the first ring 11A isalso placed on a flange portion 13A of a sidewall portion 32A. Thesecond ring 12A is placed on a stepped portion 91A of the first ring11A, and the inner circumferential side thereof fronts on the outercircumference of a susceptor 20A.

In the modified example, the second ring 12A is provided so as to coverthe separation portion 92A, and thus it is possible to further suppressthe entrance of the reactive gas flowing to the reaction chamber 2A intoa lower portion 64A of the reaction chamber. However, in order tosuppress causing the second ring 12A to block heating from heating means210 which is not shown in the FIG. 14 to the susceptor 20A, the overlapamount of the second ring 12A and the susceptor 20A is preferably small.

In the modified example, the thickness of the second ring 12A ispreferably set to, for example 0.5 mm to 2 mm. Further, the thickness ismore preferably set to approximately 0.8 mm. The second ring is formedto have such a thickness, and thus it is possible to suppress a heatloss radiation from the susceptor 20A to the second ring 12A, insofar aspossible.

FIGS. 15 and 16 are plan views illustrating an example of the susceptor20 in the embodiment of the present invention. As shown in the drawings,the susceptor 20 is provided with through holes 10A and 10B for a liftpin through which the lift pin 130 passes. In addition, as shown in FIG.16, a large number of through holes 11B may be included. A gasinterposed at the moment when the substrate is placed on the susceptorcan be let out by through holes 11B, and thus a problem that thesubstrate W slides in a horizontal direction can be solved. In addition,a case where such a susceptor 20B is used has an advantage over a casewhere the susceptor 20A is used, in terms of the uniformity in the filmthickness distribution of the substrate W or the uniformity in theresistivity distribution. This becomes more conspicuous the smallerdiameter of the through hole 11B, and the more the number of throughholes 11B. In addition, the numerical aperture is preferably set toexceed 4%, and the through holes 11B are more preferably provided notonly in concave portions 3Ba for a substrate of the susceptor, but alsoin the periphery thereto.

FIG. 17 is an exploded cross-sectional view illustrating an example ofthe gas exhaust tube 58 in the present embodiment. As shown in thedrawing, the gas exhaust tube 58 is formed so that the aperture isnarrowed toward the center as the tube moves from the reaction chamber 2side toward the gas exhaust portion 57. Thereby, an exhaust gas isstraightened at the center, and thus the improvement in exhaustefficiency is achieved.

In addition, FIG. 21 is an exploded perspective view of an outerconfiguration of the reaction chamber 2 in an epitaxial growth apparatusof the related art. As shown in the drawing, when the gas introductiontube 55 and the gas exhaust tube 58 are compared with a gas introductiontube 55′ and a gas exhaust tube 58′, respectively, a partition in eachcentral portion is removed in the present embodiment. Thereby, the flowof a gas influencing the distribution of film thickness becomessmoothly.

Meanwhile, when the numerical apertures of the gas exhaust passage 42and the purge hole 44 are excessively large, the reactive gas burrowsinto the lower portion 64 of the reaction chamber, and when thenumerical apertures thereof are excessively small, the purge gasinfluences a film formation process within the reaction chamber 2.Therefore, the aperture is formed to have an optimum value.

FIG. 18 is a perspective view illustrating an example of the upperreflector 26 in the embodiment of the present invention. As shown in thedrawing, the upper reflector 26 includes inclined portions 26 a thatreflect heat rays from the heating means 210 toward the center of thereaction chamber 2, and flattened portions 26 b that reflect the heatrays from the heating means 210 in a vertically downward direction. Onthe other hand, FIG. 22 is a perspective view illustrating an example ofan upper reflector 26′ in the epitaxial growth apparatus of the relatedart. As shown in the drawing, the upper reflector 26′ of the related artalso includes inclined portions 26 a′ and flattened portion 26 b′, butis different from the upper reflector 26 according to the embodiment ofthe present invention in the arrangement of the inclined portions 26 a.Specifically, the upper reflector 26 according to the embodiment of thepresent invention has an arrangement in which one inclined portion isadded to the center of the flattened portion 26 b′ of the upperreflector 26′ of the related art. In this manner, the inclined portion26 a and the flattened portion 26 b are arranged so that the area ratioof the inclined portion 26 a to the flattened portion 26 b becomes apredetermined ratio, and that the distributions of the inclined portion26 a and the flattened portion 26 b are not biased, and thus theuniformity in the temperature distribution of the substrate W isachieved.

FIG. 19 is a perspective view illustrating an example of the lowerreflector 65 in the embodiment of the present invention. FIG. 23 is aperspective view illustrating an example of a lower reflector 65′ in theepitaxial growth apparatus of the related art. Similarly to the upperreflector 26, the lower reflector 65 also includes inclined portions 65a that reflect heat rays from the heating means 62 toward the center ofthe reaction chamber 2, and flattened portions 65 b that reflects theheat rays from the heating means 62 in a vertically upward direction,and has an arrangement in which one inclined portion is added to thecenter of a flattened portion 65 b′ of the lower reflector 65′ of therelated art. In this manner, the inclined portion 65 a and the flattenedportion 65 b are arranged so that the area ratio of the inclined portion65 a to the flattened portion 65 b becomes a predetermined ratio, andthat the distributions of the inclined portion 65 a and the flattenedportion 65 b are not biased, and thus the uniformity in the temperaturedistribution of the substrate W is achieved.

According to such a epitaxial growth apparatus of the presentembodiment, the support portion 22 supports the ceiling plate 21,thereby allowing the distance H between the ceiling surface of thecentral portion of the ceiling plate 21 on the reaction chamber side andthe substrate W to set to less than 10 mm. Thereby, the epitaxial growthapparatus 200 in the present embodiment can suppress the spreading ofthe boundary layer, formed by the reactive gas flowing between theceiling plate 21 and the susceptor 20, to the ceiling side, and as aresult, the boundary layer becomes narrow. Then, since a gas velocitywithin the boundary layer rises, a gas density improves as a result, andthus it is possible to increase reaction efficiency in the surface ofthe substrate W. Thereby, it is possible to improve a growth rate in theepitaxial growth apparatus 200.

Meanwhile, in one embodiment of the present invention, the distance Hbetween the ceiling plate 21 and the substrate W is less than 10 mm, thedistance H between the ceiling plate 21 and the substrate W ispreferably less than 10 mm, and the distance between the surface of afilm on which the substrate W is grown and the ceiling plate 21 is equalto or more than 1 mm. The distance is set to such a range, and thus thegas flow of the reactive gas can be smoothed while the boundary layer isformed.

That is, in the reaction chamber 2 in the present embodiment, thedistance between the substrate W and the ceiling plate 21 is shorterthan in the related art (approximately 20 mm in the related art).Therefore, reaction efficiency in the substrate surface is increased bynarrowing the boundary layer, and as a result, a growth rate isimproved.

Example 1

Using the susceptor support portion including the susceptor shaft andthe substrate lift portion having the following sizes, an epitaxial filmwas grown on a semiconductor wafer under predetermined conditions.

Note

Susceptor Shaft

-   -   Width of First Arm: 3.3 mm    -   Width of Second Arm: 6.3 mm    -   Width of Third Arm: 3.2 mm    -   Diameter of Through Hole: 3.5 mm

Substrate Lift Portion

-   -   Width of First Arm: 4.8 mm    -   Width of Second Art 3.0 mm

Comparative Example 1

Experiments were performed under the same conditions as those of Example1, except other than using the susceptor support portion including thesusceptor shaft and the substrate lift portion having the followingsizes.

Note

Susceptor Shaft

-   -   Width of First Arm: 6.3 mm    -   Width of Second Arm: 6.3 mm    -   Width of Third Arm: 6.3 mm    -   Diameter of Through Hole: 3.5 mm

Substrate Lift Portion

-   -   Width of First Arm: 4.8 mm    -   Width of Second Arm: 4.8 mm

FIG. 24A is a diagram illustrating a thickness distribution map of theepitaxial film of Example 1, and FIG. 24B is a diagram illustrating athickness distribution map of the epitaxial film of ComparativeExample 1. The Both are diagrams in which the film thickness is measuredin 561 measurement points except for a range of 3 mm from the outeredge, and the distributions thereof are shown. A variation in thethickness of the epitaxial film of Example 1 shown in FIG. 24A was0.67%, and a variation in the thickness of the epitaxial film ofComparative Example 1 shown in FIG. 24B was 1.31%. Therefore, it isknown that the epitaxial film formed by the epitaxial growth apparatususing the susceptor shaft of the present invention of Example 1 has amore uniform distribution of film thickness than in Comparative Example1.

What is claimed is:
 1. A substrate support assembly comprising asusceptor having one or more susceptor through holes formedtherethrough; a susceptor shaft supporting the susceptor, wherein thesusceptor shaft includes a susceptor shaft support column and aplurality of shaft arms that extend radially from the susceptor shaftsupport column, the plurality of shaft arms each having: a shaft firstarm coupled with the support column; a second shaft arm coupled with thefirst shaft arm, the second shaft arm having an arm through hole, awidth of the first shaft arm being smaller than a width of the secondshaft arm; and a third shaft arm coupled with the second shaft arm, thethird shaft arm being in connection with the susceptor; a substrate liftportion comprising: a lift portion support column; and a plurality oflift arms coupled with the lift portion support column, each of the liftarms comprising: a first lift arm coupled with the lift portion supportcolumn; a second lift arm coupled to the first lift arm; and a pedestalportion coupled to the second lift arm; and a lift pin positioned inconnection with each of the pedestal portions and oriented to passthrough the arm through hole and the susceptor through hole.
 2. Thesusceptor support assembly of claim 1, wherein the width of the firstshaft arm is equal to or less than a diameter of the arm through hole.3. The susceptor support assembly of claim 1, wherein a width of thethird shaft arm is smaller than a width of the second shaft arm.
 4. Thesusceptor support assembly of claim 3, wherein the width of the thirdshaft arm is equal to or less than the diameter of the arm through hole.5. The susceptor support assembly of claim 1, wherein a width of thesecond arm of the substrate lift portion is smaller than the width ofthe first arm of the substrate lift portion.
 6. The susceptor supportassembly of claim 1, wherein the width of the second lift arm is thesame as the width of the first shaft arm.
 7. The susceptor supportassembly of claim 1, wherein the support column of the susceptor shaftis provided with a cap that supports the susceptor.
 8. The susceptorsupport assembly of claim 1, wherein the pedestal portion is providedwith a concave portion capable of supporting a lower end of the liftpin.
 9. An epitaxial growth apparatus comprising: a reaction chamberhaving a ceiling portion and a sidewall portion; a susceptor positionedin the reaction chamber opposite the ceiling portion, the susceptorhaving: one or more susceptor through holes formed therethrough; a firstside for receiving a substrate; and a second side opposite the firstside; a susceptor shaft supporting the susceptor and in connection withthe second side of the susceptor, wherein the susceptor shaft includes asusceptor shaft support column and a plurality of shaft arms that extendradially from the susceptor shaft support column, the plurality of shaftarms each having: a shaft first arm coupled with the support column; asecond shaft arm coupled with the first shaft arm, the second shaft armhaving an arm through hole, a width of the first shaft arm being smallerthan a width of the second shaft arm; and a third shaft arm coupled withthe second shaft arm, the third shaft arm being in connection with thesusceptor; a substrate lift portion comprising: a lift portion supportcolumn; and a plurality of lift arms coupled with the lift portionsupport column, each of the lift arms comprising: a first lift armcoupled with the lift portion support column; a second lift arm coupledto the first lift arm; and a pedestal portion coupled to the second liftarm; and a lift pin positioned in connection with each of the pedestalportions and oriented to pass through the arm through hole and thesusceptor through hole.
 10. The susceptor support assembly of claim 9,wherein the width of the first shaft arm is equal to or less than adiameter of the arm through hole.
 11. The susceptor support assembly ofclaim 9, wherein a width of the third shaft arm is smaller than a widthof the second shaft arm.
 12. The susceptor support assembly of claim 11,wherein the width of the third shaft arm is equal to or less than thediameter of the arm through hole.
 13. The susceptor support assembly ofclaim 9, wherein a width of the second arm of the substrate lift portionis smaller than the width of the first arm of the substrate liftportion.
 14. The susceptor support assembly of claim 9, wherein thewidth of the second lift arm is the same as the width of the first shaftarm.
 15. The susceptor support assembly of claim 9, wherein the supportcolumn of the susceptor shaft is provided with a cap that supports thesusceptor.
 16. The susceptor support assembly of claim 9, wherein thepedestal portion is provided with a concave portion capable ofsupporting a lower end of the lift pin.
 17. An epitaxial growth system,comprising: a reaction chamber having a ceiling portion and a sidewallportion, the ceiling portion and the sidewalls forming a process region,the ceiling portion to deliver radiation from a radiation source to theprocess region; a susceptor positioned in the reaction chamber oppositethe ceiling portion, the susceptor having one or more susceptor throughholes formed therethrough, the susceptor to: act in conjunction with theceiling portion and the sidewall portion to form the process region; andsupport a substrate during a deposition process; a susceptor shaftsupporting and in connection with the susceptor, wherein the susceptorshaft includes a susceptor shaft support column and a plurality of shaftarms that extend radially from the susceptor shaft support column, theplurality of shaft arms each having: a shaft first arm coupled with thesupport column; a second shaft arm coupled with the first shaft arm, thesecond shaft arm having an arm through hole, a width of the first shaftarm being smaller than a width of the second shaft arm; and a thirdshaft arm coupled with the second shaft arm, the third shaft arm beingin connection with the susceptor, the susceptor shaft to: support thesusceptor; and reduce the influence of heating on the susceptor; asubstrate lift portion comprising: a lift portion support column; and aplurality of lift arms coupled with the lift portion support column,each of the lift arms comprising: a first lift arm coupled with the liftportion support column; a second lift arm coupled to the first lift arm;and a pedestal portion coupled to the second lift arm, the lift arms toposition a substrate on a substrate support; and a lift pin positionedin connection with each of the pedestal portions, the lift pin totransfer force from the plurality of lift arms to a substrate throughthe arm through hole and the susceptor through hole.